Update pep-0830.rst

Author: Fidget-Spinner

peps/pep-0830.rst

@@ -1049,6 +1049,7 @@ Appendix
 
 For all graphs below, the green dots are geometric means of the
 individual benchmark's median, while orange lines are the median of our data points.
+Hollow circles reperesent outliers.
 
 The first graph is the overall effect on pyperformance seen on each system.
 Apart from the Ubuntu AWS Graviton System, all system configurations have below 2%